With a demand for an increased communication band, most of data centers (DC) and the like which provide services such as cloud services employ networks having multipath configurations. When a failure occurs in a multipath network, avoiding a disconnected path (failure avoidance) is highly requested. The failure avoidance further requests minimization of a disconnection time and influence after the failure avoidance.
In one of known techniques for efficiently switching communication paths at failure occurrence, the switching of a plurality of communication paths is performed by rewriting a flow table based on a failure detection notification from another switching device on a leaf node side.
In another one of the known techniques, when a link failure occurs, a packet failure is avoided by executing a fast path change without placing a load on the network.
Still another one of the known techniques involves acquiring information from an instrument, diagnosing the cause of a failure, and calculating a communication path that avoids a range diagnosed as a failure affecting range.
Examples of the related art include Japanese Laid-open Patent Publication Nos. 2015-91035, 2007-258926, and 2007-189615.